Robert Henry <[email protected]> writes:
> Our approach to this problem was to make the plugin sensitive to the
> execution of well-chosen instructions to turn on/turn off the actions of the
> plugin. The plugin will still be called (don't unregister it) but should
> return immediately if the on/off state is off. This will still slow the
> emulation down.
>
> My guest ISA is arm64. For that ISA, we made these choices; perhaps
> something else is better:
> asm("hint 0b0010001"); // arm64 PSB Profile Sync Buffer (turn on)
> asm("hint 0b0010010"); // arm64 TSB Trace Sync Buffer (turn off)
>
> Put these instructions in a library and arrange to have your
> application call the library functions as appropriate for the
> application's programming language.
Yeah this is the mechanism I was about to suggest. If you can guarantee
your library function is called before any of the code you want to
instrument then this can be used as a "trigger".
> ________________________________
> From: Qemu-discuss <[email protected]>
> on behalf of Kamil Garifullin <[email protected]>
> Sent: Wednesday, July 29, 2020 1:35 AM
> To: [email protected] <[email protected]>
> Subject: [EXTERNAL] QEMU plugin system
>
> Hi,
>
> I'm trying to create a plugin which will track an activity during a
> particular period of time.
>
> Can I somehow send a signal from the guest to the instrumentation plugin?
>
> For example, I want to boot linux, do some preparations, then start a
> targeted application and start my tracking. It can be both: do not inject
> instrumentation until special indication or just a special plugin event to
> set up some flags.
>
> My thoughts were to have an event which will indicate that pmon was touched.
> It allows you to do all the preparations in the guest machine, then dump
> pmons as an indicator to start tracking and then run the target application.
--
Alex Bennée
